Fix Firefox TypeError messages

Firefox will popup an error in a number of situations. Most often this is caused by a misbehaving extension.

Disable common problem extensions

Before going through complicated troubleshooting steps, try disabling these extensions:

At the top of the Firefox window, click on the Firefox buttonOn the menu bar, click on the Tools menuAt the top of the Firefox window, click on the Tools menu, and then click Add-ons. The Add-ons Manager tab will open.Click the menu button
and choose Add-ons. The Add-ons Manager tab will open.

In the Add-ons Manager tab, select the Extensions panel.

If you see Orbit downloader or 1-click YouTube downloader extensions, click the disable button next to them.

In the past McAfee SiteAdvisor, ZoneAlarm or PC Tools have also been problems.